Antibody response to respiratory syncytial virus infection in children <18 months old

Abstract

The development of a safe and effective respiratory syncytial virus (RSV) vaccine might be facilitated by knowledge of the natural immune response to this virus. The aims of this study were to evaluate the neutralizing antibody response of a cohort of healthy children <18 months old to RSV infection. During the RSV season, 89 healthy children <18 months old were enrolled and followed up weekly for 12 weeks. At each visit, a nasopharyngeal swab was obtained for RSV detection by real-time polymerase chain reaction (PCR). During the study period, 2 blood samples were drawn and they were used to determine RSV geometric mean neutralizing antibody titres (GMT) against RSV. A total of 35 (39.3%) children had RSV detected during the study period. Among RSV-positive patients, children 7 months showed a significantly higher increase in antibody response (p<0.001). A significantly higher number of patients with a 4 -fold increase in GMT were 7 months old (p D 0.02) and presented lower respiratory tract infections (LRTIs) during the study period (p D 0.01). Viral shedding was longer among children aged 7 months (p D 0.06), those with viral load 10 6 copies/mL (p D 0.03), and those with LRTIs during the study period (p D 0.03), but it was not associated with the immune response (p D 0.41). In conclusion, natural RSV infection seems to evoke a low immune response in younger children. To be effective in this infant population, which is at highest risk of developing severe LRTIs, vaccines must be able to induce in the first months of life a stronger immune response than that produced by the natural infection.

Molecular characterization and clinical epidemiology of human respiratory syncytial virus (HRSV) A and B in hospitalized children, Southern Brazil

“…1 Overall, HRSV was detected in 17% of investigated patients. This rate agrees with those of previous reports, including in Senegal (11%), 17 Italy (11%), 18 and Canada (25%). 5 HRSV infection was predominant in younger children (<6 months), and bronchiolitis was the most frequent diagnosis, which is consistent with our previous reports.…”

Serology Enhances Molecular Diagnosis of Respiratory Virus Infections Other than Influenza in Children and Adults Hospitalized with Community-Acquired Pneumonia

“…Even in the absence of serologic confirmation, a positive RT-PCR result with these viruses would be sufficient for disease association. For example, RT-PCR detected RSV in 38 children younger than 6 months who did not develop a seroresponse, which is consistent with studies that have shown that infants do not develop effective immune responses to RSV, especially following initial infection (25). Because subclinical infections with RSV are rare, RSV was likely causally related to the illness in these cases.…”

Respiratory Syncityal Virus A and B: three bronchiolitis seasons in a third level hospital in Italy

“…This could suggest an important involvement of the immune response to the virus and a role for different immune mechanisms in response to the virus in preterm infants. Indeed, there are many evidences about lack of immunity in preterm children, regarding count and activity of all subsets of T cells [36] and deficient antibody production in younger infants infected with RSV [37]. Since various components of the innate and adaptive immune response are crucial for controlling RSV infection and disease [38], more studies are needed to focus preterm specific immune response.…”